An Israeli man prays at the Western Wall, the holiest site where Jews can pray, prior to a prayer marking Israel’s Independence Day, in Jerusalem. The notion of Israel’s “Jewishness” has gained both currency and controversy recently because of Prime Minister Benjamin Netanyahu’s demand that the Palestinians recognize it explicitly as part of an agreement and plans by a broad-based group of Israelis to lobby the Knesset to declare the country a Jewish state by law.

JERUSALEM — Is Israel “the Jewish state”?

The answer may seem as obvious as the Star of David on the Israeli flag. Yet the question is starting to complicate the ambitious U.S. effort to ram through a peace deal between the Palestinians and Israel.

A broad-based group of Israelis plans to lobby the Knesset to declare the country, for the first time, a Jewish state by law. And Prime Minister Benjamin Netanyahu has demanded that the Palestinians recognize Israel’s Jewish status explicitly as part of any agreement.

“This is the Jewish land. This is the Jewish state,” he said in a speech this week to assembled U.S. Jewish leaders. “When we make an agreement it is an agreement between the nation state of the Jewish people and a nation state of the Palestinian people.”

Leading Palestinians made their opposition clear this week, insisting that by introducing the Jewish factor, Israel is drawing a red line that could doom negotiations.

“I remember the days when we were told, ‘All you need is to get the PLO to recognize Israel, and recognize Israel’s right to exist in safe and secure boundaries,’” said Hanan Ashrawi, a prominent member of the Palestinian Liberation Organization. The Palestinians did just that, she noted, as part of the 1990s interim peace agreements.

“The Jewishness of the state of Israel. this is a new addition,” she told reporters Wednesday. “We are working to establish a pluralistic, democratic, inclusive state in Palestine. Not an exclusive state based on religion, ethnicity or whatever.”

The Palestinians reject Israel’s demand for pragmatic reasons as well: Embrace of Israel as a Jewish state would amount to giving up the dreams of Palestinian refugees to return to lost properties — the so-called “right of return” which is a central sticking point in peace talks. They also say it would undermine the rights of Israel’s own Arab minority, the 20 percent of Israel’s 8 million people who are themselves ethnic Palestinians.

Even some Israelis suspect the demand is intended to complicate — but the idea has wide support nonetheless. To be criticized even for the desire to have a state of their own — a dream allowed people the world over, from the Irish to the Iranians — chafes many Jewish Israelis

Israeli academic Avraham Diskin, a self-professed lifelong dove, said a Palestinian refusal meant perpetuating the conflict. “This is the minimal test to show that their face is to peace,” he said.

Both sides are waiting to see whether the notion shows up in the framework proposal U.S. Secretary of State John Kerry is expected to table in coming weeks.

The U.S. usually doesn’t recognize countries by ethnicities, but Deputy State Department spokeswoman Marie Harf said the U.S. does recognize Israel as a Jewish state. In his State of the Union speech to Congress last month, President Barack Obama said the goals of the negotiations launched last July were “dignity and an independent state for Palestinians, and lasting peace and security for the State of Israel - a Jewish state that knows America will always be at their side.”

Kerry himself implied support for the idea of a Jewish state by advising Israelis they must pull out of Palestinian-populated lands occupied in the 1967 war in order to retain a strong Jewish majority.

Indeed, if Israelis eventually hand over significant territories to a Palestinian state, the motivation will indeed stem largely from a desire to unload their Palestinian population and leave themselves with a strong Jewish majority. An Israel that controls the West Bank, east Jerusalem and Gaza — the areas occupied in 1967 — would have some 12 million people roughly evenly divided between the two groups.

Writing in the Haaretz newspaper on Thursday, liberal columnist Ari Shavit said, “The deal on the table is clear: A Jewish state in exchange for the 1967 borders.” That, Shavit and others say, means the Palestinians must forget about a return by Arab refugees and their descendants to Israel.

But the whole notion of a Jewish state is a complicated one. By shining strong light on a matter that lives more comfortably in the shadows, Israel may be rekindling some awkward questions: Are the Jews a nation — or individuals who share a religion? Should a religion have a state? Should a state have a religion?

And beyond that lies a bigger issue still: Is the idea of a nation-state — with members of that nation fretting over how to stay dominant numerically — not somehow unbecoming in the age of globalization?

The original Zionists of the late 19th century were mostly secular people inspired by the rise of European nations on the ashes of empires. Convinced the Jews needed a state of their own as well, they settled on the Holy Land, from which Jews were expelled by the Romans two millennia ago.

In November 1917 the Zionist movement persuaded Britain — who would soon receive a League of Nations mandate to rule Palestine — to issue a declaration supporting “the establishment in Palestine of a national home for the Jewish people.” Thirty years later, with British colonial rule nearing its end, the newly established United Nations voted for partition of the area into independent “Arab and Jewish States.”

Israel’s 1948 Declaration of Independence was essentially a national statement, proclaiming that Palestine — referred to interchangeably as “the land of Israel” — was “the birthplace of the Jewish people.” Zvi Hauser, who until recently served as Netanyahu’s Cabinet secretary, lamented this week that this declaration was never followed by a constitution cementing the country’s status as the Jewish state.

“The Jewish people is not just a religion. It is also a national group that has a right to self-actualization,” he said.

In fact, the question of what it means to be a Jew is a matter of debate — abroad and in Israel itself, where Orthodox rabbis fight to retain a monopoly over religious conversions that have the unusual corollary outcome of constituting a membership ticket to a “people” as well.

“It’s hard to compare the matter to other countries because of the unique aspect of Judaism,” said Malcolm Hoenlein, the executive vice chairman of the Conference of Presidents of Major American Jewish Organizations.

“It is not just a religion or a nationality or an identity — it is all in one,” said Hoenlein, who organized the conference that Netanyahu addressed.

Israel’s law of return combines the heritage and religion definitions. It grants citizenship to anyone with at least one Jewish grandparent, as well as to converts who have no Jewish heritage but are recognized by the Orthodox rabbis.

Consensus on the matter is extremely hard to find.

Many Jews around the world see their identity as a primarily a matter of religion. Plenty of Israelis think that a “Jewish state” should be more of a theocracy, outlawing work on the Sabbath, for example. At the same time, many Jews in Israel and elsewhere are not at all religious and view themselves as Jewish simply because they were born to Jewish parents — a situation not unlike that of ethnic Irish or Japanese.

Most confounding, perhaps, are the ethnic divisions that persist between the Jews themselves.

Israel’s founders were overwhelmingly European Jews, and that group — known as Ashkenazim — was numerically dominant among Jews before the Nazi Holocaust, diverse yet cohesive enough to lend credence to a national movement.

But the reality today in Israel is diverse. Almost half of the Jewish population of 6 million is descended from the Arab world — their background, history, and even appearance often starkly different from their European cohorts. Tensions over everything from music to food to prayer styles lurk just beneath the surface.

In this situation, it is not uncommon for Israelis to refer to each other, not always with admiration, by distant country of origin — as “Moroccans” and “Yemenites,” or “Bulgarians” and even “Americans.”

As they observe all this, skepticism among Palestinians — whose communities were displaced by the Zionist movement — seems easy to understand.

“Judaism is a religion like Islam and Christianity,” said Mustafa Barghouti, a prominent Palestinian legislator. “Israel is a state, a nationality that represents all the groups and ethnicities in Israel — including the Palestinians.”